#include <iostream>
#include <cmath>
const double PI = 3.14159265358979323846;
double calculateArea(double radius) {
return PI * pow(radius, 2);
}
double calculateCircumference(double radius) {
return 2 PI radius;
}
int main() {
double radius;
std::cout << "Enter the radius of the circle: ";
std::cin >> radius;
double area = calculateArea(radius);
double circumference = calculateCircumference(radius);
std::cout << "Area of the circle: " << area << std::endl;
std::cout << "Circumference of the circle: " << circumference << std::endl;
return 0;
}